We are proposing to continue our work to further develop a clinically useful tool to evaluate central nervous system organization in preterm infants less than 1500 grams at birth. This work has the potential to provide a means of earlier identification of preterm infants who are at risk for neurobehavioral sequelae. The specific aims are to: 1)examine the relationship between nutritive sucking patterns, and other neurobehavioral assessments (physiologic parameters, Brazelton Neonatal Behavioral Assessment Scale and state) in the newborn period; 2) examine the relationship between preterm infant nutritive sucking patterns at 34 weeks post- conceptional and sucking patterns at term and I month corrected gestational age; 3) examine the relationship between neonatal neurobehavioral assessments and neurobehavioral development through the first year of life. The sample will include 336 preterm infants with gestational ages ranging from less than 26 to 34 weeks. In hospital data collection instruments include the Kron Nutritive Sucking Apparatus, Anderson Behavioral State Scale, and the Brazelton Neonatal Behavioral Assessment Scale. Preterm infants will have weekly sucking measurement from 32-33 post-conceptional age until hospital discharge. Cardiovascular measurements and behavioral state will be measured concurrently. During a 1-year follow-up, data collection will include nutritive sucking measurement, behavioral and cognitive assessments. Data analysis will include means, standard deviations, standard error of the means, t-tests, MANOVAs, correlation procedures and time series analysis. It is anticipated that this investigation will: a) provide additional reliability and validity data on nutritive sucking measures as a means of assessing neurobehavioral development; b) further our understanding of the inter-relationship of nutritive sucking with physiologic, neurobehavioral and psycho- motor assessments; and c) increase our potential to identify those infants who are most at risk for abnormal development. We recognize that longitudinal assessments need to be continued longer than the first year of life. Therefore, this proposal represents the first phase of this work.